1. Technical Field
The present application relates generally to a cellular communication system and, in particular, to a method for handling an alarm according to a change in the type of channel card in a CEUR (Channel Element Unit Rack) of a digital cellular system.
2. Description of Related Art
In general, mobile communication systems such as PCS (Personal Communication Service) and CDMA (Code Division Multiple Access) systems include a plurality of BTS (Base Station Transceiver Subsystem) for serving mobile terminals located in corresponding regions, a plurality of BSCs (Base Station Controllers), a plurality of BSMs (Base Station Manager Systems) for managing and controlling a plurality of BSCs and BTSs, a plurality of MSCs (Mobile Switching Centers), and a plurality of HLRs (Home Location Registers).
A communication system which operates per unit cell is called a cellular system. The term xe2x80x9ccellxe2x80x9d refers to an area which is covered by a BTS, and a cell is generally divided into one omni-cell or three sector cells. The service area which this cell covers hierarchically expands from a BTS area to a BSC area and to a MSC area. A mobile station in a given cell communicates with the BTS designated to the cell via communication channels. A forward channel refers to a communication link formed from the BTS to the mobile station, and a reverse channel refers to a communication link formed from the mobile station to the BTS. The forward channels that are typically formed from the BTS to the mobile station include a pilot channel, a sync channel, a paging channel, and a plurality of forward traffic channels. The reverse channels that are typically formed from the mobile station to the BTS include an access channel and a reverse traffic channel. The mobile station and the BTS transmit and receive voice and data by utilizing the traffic channels.
Each BTS is assigned operating frequencies according to its system capacity, and each frequency channel is called a FA (Frequency Assignment). In general, a CDMA (Code Division Multiple Access) communication system contains a plurality of access channels on a single frequency channel, the different access channels being separated by different frequency offsets and coding sequences.
The main processor of the BSC is called a CCP (Call Control Processor), and the main processor of the BSM is called a BCP (BTS Control Processor). In addition to these processors, a CDMA and PCS system utilizes the following processors: an ACP (Alarm Control Processor); an alarm processor for BER (Bit Error Rate) between the BSC and the BTS for controlling a clock device and receiving synchronization signals from a GPS receiver so as to clock synchronize a call from the BTS; a CSP(Common Channel Signaling Processor) for transmitting signal information without error between the BTS and the BSC; a SIP (Selector Interface Processor) (which operates in the link layer) for controlling call connection and a radio link; a SVP (Selector and Vocoder Processor) for modulating and demodulating voice data; a CIP (Channel Interface Processor) for managing channel elements and controlling the interface; a TIP (Transceiver Interface Processor) for managing a transceiver and controlling the interface; and BTP (BTS Test Processor) for connecting a terminal to a BTS so as to test the functions.
In addition, high capacity inter-processor communication node processor board assemblies such as a GHIPA (Gateway High Capacity Inter Processor Communication Node Processor Board Assembly) connected to the BSM, a LHIPA(Link High Capacity Inter Processor Communication Node Processor Board Assembly) connected to the BSC, and a BHIPA (BTS High Capacity Inter Processor Communication Node Processor Board Assembly) may be included.
An alarm which occurs in the above-structured digital cellular system is handled through the BSM by informing an administrator whether or not a specific device is properly working. Specifically, after a physical location table is generated, when the BTSs and devices of the BSC are working abnormally, the system informs the administrator of each corresponding physical location so as to inform the administrator of the alarm. In order to handle an alarm signal properly, device names and a maximum equipment number, a shelf, and a rack, which comprise each system must be predefined when the physical location table is generated. If the above-mentioned items are changed, a new physical location table must be generated again to incorporate the changes.
The digital cellular communication systems mentioned above also, in general, include a DCEA (Digital Channel Element Assembly) which is a channel card with a capacity of four channels, and an ECEA (Eight Channel Element Assembly) which is a channel card with an eight channel capacity.
Conventionally, when handling an alarm, the channel card is typically defined as a DCEA type in the physical location table, and an alarm generated in a ECEA-equipped system is handled as an exceptional case. The types of the channel cards that are utilized must be defined according to the system so as to handle the alarm of the different channel card types. After changing a channel card, each BTS and BSC must initialize the files which contain information regarding a previously-occurred alarm. To accomplish this, after deleting the existing files, the processor which handles the upper-rank alarm must be terminated and regenerated, so as to read the information of the changed channel card. The upper-rank alarm processor (or the FLMX (Fault Management Processor)) then collects alarm information transmitted from each BTS and BSC and informs the administrator of the alarm information visually and audibly.
Referring now to FIG. 1, a diagram illustrates a rack of the channel card of the BTS. Each CEBB (Channel Element Back Board) has two kinds of channel cards, i.e., the DCEA and the ECEA. Each CEBB, which is comprised of either 4 ECEAs or 8 DECAs, supports 32 channel elements. The areas denoted by xe2x80x9cblankxe2x80x9d represent empty slots and a plurality of fans are included to cool the rack. The system of FIG. 1 also includes an ACCA (Analog common Card Assembly).
A conventional method for handling the alarm executed by the FLMX will now be discussed. Initially, in order to change the channel cards, the power supply to the rack equipped with the channel cards must be turned off. The changes of the channel cards are performed per unit FA. If a user turns off the rack power, an alarm will occur in the FA of the corresponding rack, and the alarm will be reported to the administrator. The user may then change the old channel card type to a new channel card type and turn the power on. Thereafter, a new alarm will occur in the newly changed channel card or other devices (except the rack), and the FLMX reports the alarm to the administrator.
But since the old alarm of the previous channel card has already occurred, the new alarm cannot be recognized and remains. The data of the file which stores the existing alarm data of the corresponding BSC must be deleted so as to remove the old alarm. In addition, the FLMX must be killed so that the new (i.e., different type of) channel card can be read. A file can then be generated so as to recognize the new alarm.
With this conventional method, because the new alarm data reported to the FLMX cannot be stored to the file, the new alarm data generated from the new channel card may be lost. As a result, the alarm generated from the system is not identical with the alarm information reported to the administrator.
Therefore, in order to restore the alarm information normally, the alarm information should be requested from the lower processors (i.e., the BCP) so that the real state of the system may be identical with the alarm information. Particularly, the conventional method for handling the alarm requires the following additional process.
First, the administrator must manually remove the files which store the alarm information of the previous channel card. Second, the FLMX must be killed and generated again, so as to regenerate a file. Third, the system must request the lower processors of the alarm information, so that the alarm information which may be lost be identical with that of the real system.
There are several problems associated with the conventional method discussed above. For instance, the method results in time waste and other difficulties since the administrator must manually type the command codes and perform them. In addition, it is not proper for the FLMX (i.e., the upper processor for handling the alarm) to make identical the real state of the system and the alarm information.
It is therefore an object of the present invention to provide a method for handling the alarm according to the changeable channel card types without killing the FLMX and requesting alarm information to the lower processor (or BCP).
In one aspect, a method for handling an alarm when changing channel card types in a digital cellular communication system, comprises the steps of:
(a) replacing an old channel card type with a new channel card type and checking changed information;
(b) setting up an identification number of a CIP (Channel Interface Processor) and a number of iteration counts based on a form of BTS;
(c) setting up a location of a channel element which will be handled per CIP by utilizing the identification number of the CIP;
(d) determining a channel element type in the location of channel element and assigning an alarm code for the channel element type;
(e) determining whether an alarm occurs in the location of the channel element and clearing the alarm if it is determined that an alarm occurs;
(f) setting up the location of the new channel card by utilizing the old channel card type and the location of the channel element and re-setting the identification number of the CIP;
(g) determining whether steps (c) through (f) have been iterated a maximum number of times and returning to step (c) if it is determined that the steps (c) through (f) have not been performed a maximum number of times, the maximum number of times being equal to the maximum number of channel elements per CIP;
(h) reading and storing changed form information per channel element if it is determined that the steps (c) through (f) were iterated the maximum number of times;
(i) increasing the CIP identification number by two so as to process a next alarm; and
(j) determining whether steps (c) through (i) have been iterated for the number of iteration counts set up in step (b), returning to step (c) if it is determined that steps (c) through (i) have not been iterated for the number of iteration counts, and terminating the process of handling the alarm if it is determined that steps (c ) through (i) have been iterated for the number of iteration counts.
These and other aspects, object and advantages of the present invention will become apparent in the following description of preferred embodiments which is to be read in connection with the accompanying drawings.